python 内置函数 装饰器

>>> str = "for i in range(0,10): print(i)"
>>> c = compile(str,‘‘,‘exec‘)
>>> exec(c)
0
1
2
3
4
5
6
7
8
9
>>> str2 = "3*3 + 4*4"
>>> c2 = compile(str2, ‘‘, ‘eval‘)
>>> eval(c2)
25

>>> exec(‘if True: print(100)‘)
100
>>> exec(‘‘‘
x = 200
if x > 100:
    print(x + 200)
‘‘‘)
400

>>> x = 1
>>> print eval(‘x+1‘)
2

>>> divmod(10,3)
(3, 1)
>>> 

>>> li = [11,11,33,11,44,44,55]
>>> max(li, key=li.count)
11

>>> round(2.345)
2
>>> round(2.345,2)
2.35

>>> isinstance(li,list)
True
>>> 

def foo(arg, a):
	x = 1
	y = ‘xxxxxx‘
	for i in range(10):
		j = 1
		k = i
	print locals()
#调用函数的打印结果
foo(1,2)
#{‘a‘: 2, ‘i‘: 9, ‘k‘: 9, ‘j‘终端: 1, ‘arg‘: 1, ‘y‘: ‘xxxxxx‘, ‘x‘: 1}

>>> def func(x):
	x = x + x
	return x
>>> list(map(func,li))
[2, 4, 6, 8, 10]
>>> 

>>> li
[1, 2, 3, 4, 5]
>>> list(filter(lambda x: x> 3, li))
[4, 5]

>>> list(range(10))
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> list(range(10,1,-2))
[10, 8, 6, 4, 2]

>>> l1 = [1,2,3,4,5]
>>> l2 = [‘a‘,‘b‘,‘c‘,‘d‘]
>>> zip(l1, l2)
<zip object at 0x0000000003419948>
>>> list(zip(l1, l2))
[(1, ‘a‘), (2, ‘b‘), (3, ‘c‘), (4, ‘d‘)]

#### 第一波 ####
def foo():
    print ‘foo‘
 
foo     #表示是函数
foo()   #表示执行foo函数
 
#### 第二波 ####
def foo():
    print ‘foo‘
 
foo = lambda x: x + 1
 
foo()   # 执行下面的lambda表达式，而不再是原来的foo函数，因为函数 foo 被重新定义了

>>> def outer():
        print("outer called.")
        
>>> outer()
outer called.

>>> def outer(func):
    print("before outer called.")
    func()
    print("  after outer called.")
    return func
>>> def f1():
    print(" f1 called.")
    
>>> f1 = outer(f1)
before outer called.
 f1 called.
  after outer called.

>>> def outer(func):
    print("before outer called.")
    func()
    print("  after outer called.")
    return func
>>> def f1():
    print(" f1 called.")
>>> @outer
    def f1():
	print(‘f1 called‘)
	
before outer called.
f1 called
after outer called.

>>> def outer(func):
        def inner():
            print("before func called.")
            func()
            print("  after func called.")
            # 不需要返回func，实际上应返回原函数的返回值
        return inner
>>> 
>>> @outer
def f1():
	print(‘f1 called‘)
	
>>> f1()
before func called.
f1 called
after func called.

>>>def outer(func):
      def inner(a, b):
          print("before func called.")
          ret = func(a, b)
          print("  after func called. result: %s" % ret)
          return ret
      return inner
 
>>>@outer
def f1(a, b):
    print(" f1(%s,%s) called." % (a, b))
    return a + b
>>>f1()
before func called.
f1(a,b) called
after func called.

>>>def outer(func):
      def inner(*args, **kwargs):
          print("before func called.")
          ret = func(*args, **kwargs)
          print("  after func called. result: %s" % ret)
          return ret
      return inner
 
>>>@outer
def f1(a, b):
    print(" f1(%s,%s) called." % (a, b))
    return a + b
>>>@outer
def f2(a, b, c):
    print(" f2(%s,%s,%s) called." % (a, b, c))
    return a + b + c
>>>f1()
before func called.
f1(a,b) called
after func called.
>>>f2()
before func called.
f1(a,b,c) called
after func called.